1. Technical Field
The present invention relates to a MEMS device, an electronic apparatus, and a manufacturing method of the MEMS device.
2. Related Art
Generally, there is an electro-mechanical system structure having a structure which is called a micro-electro-mechanical system (MEMS) device, is formed using a micro-processing technique, and is mechanically movable. For example, JP-A-2009-51005 discloses a MEMS vibrator (a MEMS structure) which is formed along with a semiconductor device on a semiconductor substrate and includes a fixed electrode (a lower MEMS structure layer) and a movable electrode (an upper MEMS structure layer). The MEMS vibrator with this structure forms an electrostatic vibrator in which the movable electrode is vibrated by an electrostatic force of electric charge which is generated by an AC voltage applied between electrodes, and a resonance frequency signal unique to the vibrator is output between the electrodes.
Since the resonance frequency, the Q-value, or the like of the output signal depends on dimension accuracy of the MEMS structure which is an electrode, an MEMS vibrator with stable and excellent characteristics can be obtained using a micro-processing technique which has been used for semiconductor manufacturing.
However, recently, with the progress of further miniaturization of a MEMS device, there is a problem in that a stable characteristic cannot be obtained only with management of the dimension accuracy in a manufacturing process in the MEMS vibrator disclosed in JP-A-2009-51005. Specifically, the problem is that a positional relationship such as a gap between the fixed electrode and the movable electrode or an overlapping length thereof slightly changes due to a stress remaining or occurring in a foundation portion which is laminated on a semiconductor substrate and on which the MEMS vibrator including the fixed electrode and the movable electrode is formed, thereby changing the output characteristics of the MEMS vibrator.